The main health risks of urolithiasis are local damage to the urinary tract, obstruction of the urinary tract caused by stones, and complications of urinary tract infection. Local injury: Small stones can move freely in the urinary tract and easily abrade the mucosa of the urinary tract causing bleeding and renal colic, but this local injury is still relatively mild. Large fixed or antler-shaped stones, although not very painful, can cause long-term pressure on the mucosa of the urinary tract, resulting in epithelial detachment, tissue ulceration and adhesions between the stone and the ureteral wall, and in serious cases, may cause cancer. Urinary tract obstruction: Kidney and ureteral stones tend to stay at the pelvic ureteral junction and ureter across the iliac vessels, causing urinary tract obstruction. After urinary tract obstruction, the ureter and renal pelvis above the obstruction will be dilated and water will accumulate. Hydronephrosis can be classified as mild, moderate or severe. In hydronephrosis, the kidney parenchyma is squeezed and affects the kidney function. If hydronephrosis is not solved for a long time, the whole kidney can lose its function. If there is obstruction in both urinary tracts, it will lead to uremia. Urinary tract infection: secondary infection of hydronephrosis can form pus in the kidney, and serious urinary tract infection may also cause sepsis, threatening human life. In addition, urinary tract infections promote the formation of stones and make the existing stones increase rapidly.